1. Field of the Invention
The present invention relates to a cassette storing a plurality of electronic component chips, which provides a form not only applicable to packaging and transportation of electronic component chips but also suitable for providing a large number of electronic component chips to an apparatus for supplying electronic component chips, such as a chip mounting apparatus for mounting the electronic component chips on printed circuit boards, etc.
The term "electronic component chip" herein used includes not only a "chip-like electronic component", being a finished product, but also a "chip-like electronic component body", being a partially fabricated item, which is to be connected with lead wires or the like in a later step.
2. Description of the Prior Art
Electronic component chips have been generally packaged by one of a taping system, a magazine system, a bagging system and the like, and the taping system currently forms the mainstream because of its high reliability of automation in mounting. Packing of electronic component chips by the taping system is disclosed in U.S. Pat. No. 4,298,120 entitled "Chip-like Electronic Component Series and Method for Supplying Chip-like Electronic Components" issued on Nov. 3, 1981 and granted to Kaneko, et al.
FIG. 20 shows exemplary packaging of electronic component chips by the taping system. This system comprises a tape member 2 rolled on a reel 1, for example, which tape member 2 is provided with a plurality of cavities distributed along its longitudinal direction to receive electronic component chips one by one in the cavities. In the taping system as shown in FIG. 20, the tape member 2 is in sandwich structure formed by a base tape 3 of cardboard, for example, and cover tapes 4 adhered to both surfaces thereof, as shown in section in a partially enlarged manner. The base tape 3 is provided with cavities 5, which are through-holes formed in the direction of thickness, to receive straight-sided electronic component chips 6, for example.
The aforementioned taping system can be directly applied to a chip mounting apparatus. Namely, one of the cover tapes 4 is stripped from the base tape 3 to open the cavities 5, thereby to discharge the electronic component chips 6. Such operation can be continuously performed while feeding the tape member 2 in the longitudinal direction.
In the magazine system, on the other hand, a plurality of electronic component chips, being in an aligned state, are received in a magazine. Such a magazine system is also directly applicable to a chip mounting apparatus.
In the bagging system, electronic component chips are simply packed in an appropriate bag, most inexpensively in the three types of packaging systems.
However, all of the aforementioned three types of packaging systems have problems to be solved.
In the taping system, submaterials other than the electronic component chips 6, such as the reel 1, the base tape 3 and the cover tapes 4 as shown in FIG. 20, are at a high cost. Further, the transportation cost per electronic component chip is increased due to the high cost relating to the submaterials. Further, the electronic component chips 6 are generally received one by one in the cavities 5, whereby a considerably long time is required to completely charge a prescribed number of electronic component chips 6. In addition, equipment for taping the electronic component chips 6 requires a relatively complicated mechanism, whereby the equipment cost is increased. In a chip mounting step on a consumer side, further, a plurality of reels 1 are generally transversely arranged to process the tape members 2 drawn out from the reels 1 on the same plane, whereby an occupied floor space of chip mounting equipment is inevitably increased. Since the number of the electronic component chips 6 held in the tape member 2 rolled on a single reel 1 is limited, the reel 1 must be replaced by a new one when all of the electronic component chips 6 are discharged. The chip mounting apparatus must be temporarily stopped in this case. When the chip mounting apparatus is operated with a plurality of reels 1, the entire apparatus must be stopped even if the electronic component chips 6 are completely discharged merely in a single reel 1. Further, if the reels 1 carry different numbers of electronic component chips 6, the electronic component chips 6 are separately used up in the respective reels 1. Thus, the operation rate of the chip mounting apparatus is lowered by such factors.
On the other hand, in comparison with the taping system, the magazine system substantially requires no large occupied floor space in chip mounting equipment and the transportation cost thereof is relatively low, whereas the cost is increased by submaterials such as the magazine and a stopper for retaining the electronic component chips in the magazine in transportation as well as equipment for magazinization similarly to the taping system, while a long time is required for such magazinization. Further, the critical defect of the magazine system as compared with the other systems is that the number of electronic component chips receivable in a single magazine is small. Thus, rotably caused in this system is the problem of lowering the operation rate of the chip mounting apparatus, as hereinabove described with reference to the taping system.
In the bagging system, equipment required for packaging is at a low cost and the packaging time can be reduced. However, although submaterials required for simply bagging a prescribed number of electronic component chips are at a low cost, some means must be adopted in transportation, in order to prevent breakage of the electronic component chips etc. In general, bags each containing a plurality of electronic component chips are packed in a small box, and a plurality of such small boxes are packed in a box of medium size. Then, a plurality of such medium-sized boxes are finally packed in a large box for shipment. Thus, in view of packaging through such stages, the bagging system is not necessarily at a low cost. Further, a parts feeder must be employed in the chip mounting step, and a plurality of such parts feeders require a large floor space. In particular, there is an idea of arranging storage vessels or hoppers employed in the above parts feeder in closer contact with each other, thereby to reduce the occupied floor space. In this case, however, the number of electronic component chips stored in a single storage vessel or hopper must inevitably be reduced, and hence new electronic component chips must be frequently fed to the storage vessel or hopper. Further, in order to closely arrange a number of storage vessels or hoppers in a narrow floor space, openings of the storage vessels or hoppers must be made small narrowed as a matter of course, whereby it is difficult to supply prescribed electronic component chips to prescribed ones of the storage vessels or hoppers from the exterior. Different types of electronic component chips may be erroneously dropped in adjacent storage vessels or hoppers.
In recent years, electronic component chips are so extremely reduced in size that it may be difficult to apply the taping system or the magazine system to such miniature electronic component chips, setting aside the bagging system.